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Old 10-02-2012, 07:31 PM   #71
Art
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City: SF Bay Area
Vessel Model: Tollycraft 34' Tri Cabin
Join Date: Feb 2011
Posts: 12,569
[QUOTE=psneeld;106256]

"... this month's winner, Commander David E. Davis, USN. writes:
Sorry but...it depends. According to the U.S. Navy Towing Manual, Appendix H, when you determine the strain for a towed vessel the propeller resistance is a function of the projected waterplane area of the prop, times a constant (3.737), times the velocity of the tow squared.
So the faster you tow, the faster the prop resistance increases. For example: for a typical destroyer the towing resistance attributed to the prop(s) at 6 knots is 34k pounds while at 8 knots the same prop(s) yields 61k pounds.

In an offhand way... the above description/formula reminds me of a problem when approaching the speed of light... eventually the mass doing so becomes infinite! Or, for layman terms in regard to the prop drag on boats moving in the range of 3 to 12 knots with a freewheel or static prop, i.e. any number of our boats on TF: “Angle of the dangle is directly proportionate to hypotenuse of the square”. In other words - Although this gives us all plenty to chat about and learn from - - > It ain't No Big Deal in the long or short run!
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